Is it possible to synch two apple watches to the same phone?

You can have two watches, but only one can be paired to your iPhone at any given time. Each time you want to switch watches, you can unpair the one you are using and re-pair your iPhone with the other.

The Apple Watch app on your iPhone takes backups of your watch automatically, including a refresh when you unpair via the app. Each time you re-pair a watch, you can choose to restore it from the most recent (or another) backup when offered the option by the app during set up. Most data and settings will be restored, with some exclusions (eg passcode, cards used for Apple Pay). If you use Apple Pay on your watch, you would need to add your card(s) back each time after switching.

Unpair your Apple Watch and iPhone - Apple Support

Set up your Apple Watch - Apple Support

If you would prefer switching between two watches to be made easier, you can submit feedback to Apple here:

https://www.apple.com/feedback/watch.html